Reminiscent of an artist’s pallet, this is the Emi Koussi volcano in northern Chad, imaged by the European Space Agency (ESA) Copernicus Sentinel-2B satellite.
Emi Koussi lies at the southeast end of the Tibesti Mountains. At almost 3,500 meters, this pyroclastic shield volcano rises high above the surrounding sandstone plains. It is not only the highest mountain in Chad, but also the highest in the Sahara. Calderas, or depressions, can be seen nestling in the cap of the volcano. These are a result of magma erupting quickly and the surface collapsing into the partially emptied magma chamber. Emi Koussi is extinct, and it’s not known when it last erupted.
The lack of vegetation allows wind and water to carve long grooves in the rock. These grooves can be 30 meters deep and several kilometers long.
Image processing reveals differences in the minerals of the rock. For example, the green around the cone of the volcano is old lava, while sandstone in the surrounding area appear in reds and yellows.
Image credit: Contains modified Copernicus Sentinel data (2017), processed by ESA